He was screened by TSA officials and then headed to an airport concourse, where he boarded an 11:15 a.m. flight on Delta to Sin City.

The flight crew became suspicious of the nine-year-old's travel circumstances and called the Las Vegas Metropolitan Police, who took the boy into custody upon landing, Hogan said. He was then transferred into the care of child protective services.

"The fact that the child's actions weren't detected until he was in flight is concerning," he said. "More than 33 million people travel through Minneapolis-St. Paul International Airport every year, and I don't know of another instance in my 13 years at the airport in which anything similar has happened.

"He was able to get onto an airline where he didn't have a ticket and made it five states across the U.S.," he said. "If it hadn't been for alert airline employees on our end, he probably never would have been discovered."

Cassell did not know if the boy had been reunited with his family, but said that the boy's mother, child protective services and Delta Airlines were working to develop a plan to bring him home after the incident occurred.

A spokesman for Delta Airlines said the incident was under investigation, but would not elaborate on the details of the case.